human5892 said:
I do quite a few of the things already mentioned in here, but to add one:
I will suddenly and arbitrarily have an intense recall of a previous embarrassing moment, usually involving something I said. The moment can be relatively recent or years old -- it doesn't seem to matter. The memory only lasts a few seconds, but during that time it's almost physically painful -- I usually wince and sometimes even mutter something under my breath. This happens a few times a week and is insanely irritating.
That's me.

Though my moments are usually more recent focused. Last month was prom, so embarrassing moments ahoy. Those follow two weeks were quite painful. >_> Even now, at the remembrance of such events, my stomach shakes in fear.
When I was little, and rarely do now, while sitting in a car I would have this imaginary ball that I would bounce over trees and power lines. It was sort of like a game and the ball couldn't touch a tree or a power line.
Probably the weirdest thing I do involves my hands. Whenever I am vividly imagining something, I will do these weird hand motions. It's kind of hard to describe it. I did it a lot when I was a kid and some people remember me for this. I don't do it in public anymore, though I sometime do it in private. It's a very unconscious thing.
Also, I'm addicting to holding a pencil, by the tip, with my mouth and sometimes carry one with my mouth. In recent times I'm too self conscious to do in the hallways at school, but I'll do it in the classroom. I've had people tell me it looks like I'm smoking. That has led me to fantasize about having a cigarette in my mouth all the time. Though, I don't intend to ever smoke. Going along with that, I also fantasize about dressing up like a noir detective. Just today I was thinking up lines I would say.
I'm addicting to using hand sanitizer. I don't do it to be healthy really, just when my hands feel weird. I'll even use it on my pencils, though it's because I realize how unhealthy my pencil habit is.